Device and method for sharpening multiple blade knives

ABSTRACT

For the purpose of developing a device for sharpening multi-blade cutters, the invention proposes a device for sharpening multi-blade cutters having at least one motor and a holding table that is mobile relative thereto, the holding table comprising a holding member for clamping the cutter and a motor axis of the motor being disposed crosswise to the main shifting axis of the holding table.

[0001] The invention relates to a device for sharpening multi-blade cutters having at least one motor and a holding table that is mobile relative thereto, said holding table comprising a holding member for clamping the cutter and to a method for sharpening multi-blade cutters.

[0002] Currently existing devices for sharpening multi-blade cutters provide for clamping the multi-blade cutter in such a manner into the device that the multi-blade cutter, after having been sharpened in a first region, has to be positioned and oriented anew within the device, often with some expense, for sharpening a second region thereof.

[0003] In some devices, the respective one of the clamped multi-blade cutters is scanned by a fan laser for example prior to performing the actual sharpening process in order to thereby inter alia determine the accurate sharpening position.

[0004] A drawback of the known devices for sharpening multi-blade cutters is that the multi-blade cutters are to be adjusted anew, with relatively high expense, between the first sharpening process performed on the first blade and the second sharpening process performed on the second blade in order for example to achieve symmetrical sharpening of the to-be sharpened areas of the multi-blade cutter.

[0005] It is the object of the invention to develop such type devices for sharpening multi-blade cutters.

[0006] This object is achieved by a device for sharpening multi-blade cutters having at least one motor and a holding table that is mobile relative thereto, said holding table comprising a holding member for clamping the cutter and the motor axis of a motor being disposed crosswise to the main shifting axis of the holding table. The motor of the device primarily serves to drive a sharpening tool for sharpening the cutting blades of the multi-blade cutter.

[0007] This permits to adjust the sharpening angle in a simple manner. The motor axis to which the sharpening tool is mounted may hereby be advantageously adjusted in a manner that permits for example to almost always adjust an optimum sharpening angle. In disposing the motor axis transversely to the main shifting axis of the holding table, said holding table will not travel parallel to the motor axis as usual but will rather move at an angle thereto. This makes it, inter alia, possible to utilize other sharpening tools than the conventional sharpening discs for sharpening the blades.

[0008] In order to permit particularly efficient sharpening of multi-blade cutters that are more specifically sold by the name of left- and right-handed blades, it is advantageous if the holding member is disposed on the holding table by means of a fixing member. The distinction between left- and right-handed blades is for example made when utilizing a multi-blade cutter in a lawn mower. In accordance with the invention the holding member is thereby disposed on the fixing member by means of a clamping means.

[0009] In order to for example allow for advantageous and fast processing of left-handed and right-handed blades using the sharpening device, it is particularly advantageous if the device is provided with at least one additional fixing member for a holding member. One holding member is for example disposed on the right side of the sharpener tool for sharpening right-handed blades and another holding member is disposed on the left side of the motor for preferably sharpening left-handed blades. Depending on the utilization, the holding member may then be disposed either on the left or on the right fixing member. If a right-handed blade is for example to be sharpened, it will be supplied to the sharpener tool from the right. By contrast, if a left-handed blade is to be sharpened, it will be supplied to the sharpener tool from the left.

[0010] In order for example to change the adjustment of the device for sharpening a multi-blade cutter from an adjustment suited for a right-handed blade to an adjustment for a left-handed blade or vice versa, it is particularly advantageous if the holding member is disposed so as to be detachable. This makes it possible to readily detach from a first fixing member a holding member that is secured on said first fixing member, on the right fixing member for example, and to attach it to the other fixing member, for example to the left fixing member. The holding member is thereby fixable relative to the holding table.

[0011] It is particularly advantageous if the holding member comprises a holding-down clamp. This holding-down clamp serves to secure the multi-blade cutter, in the symmetry point of the multi-blade cutter for example, on the holding table of the device, using a simple construction.

[0012] In a preferred implementation variant, there is provided that the holding member comprises a slide rod clamp. Said slide rod clamp serves on the one side to secure the multi-blade cutter on the holding table of the sharpening device and on the other side to perform this fixation and to release it in a particularly uncomplicated manner.

[0013] The holding member as it has been described herein above permits, inter alia, to position, secure and change the position of the multi-blade cutter and to replace the entire multi-blade cutter in a particularly simple manner which, as a result thereof, permits to save considerable time.

[0014] It is advantageous if the holding member is fixable relative to the holding table. The securability of the holding member relative to the holding table is particularly advantageous for multi-blade cutters since, in accordance with the invention, the positioning is considerably facilitated, more specifically when, after sharpening of the first blade and prior to sharpening a second blade of the cutter, the multi-blade cutter is reoriented. This results, inter alia, in a considerable reduction of the overall processing time and more specifically of the time needed for having a multi-blade cutter ready for processing.

[0015] The term “main shifting axis of the holding table” is to be substantially construed herein as the main direction of travel of the holding table during a sharpening process.

[0016] It is thereby particularly advantageous if a cup wheel is mounted to the motor axis. The cup wheel, which may now, thanks to the crosswise orientation of the motor axis, be advantageously utilized on a device for sharpening multi-blade cutters as well, permits to achieve far more accurate sharpening of the blades of the multi-blade cutter, more specifically as far as the sharpening angle is concerned.

[0017] More specifically if the cup wheel comprises a boron nitrite material, the amount of dust produced during sharpening is considerably reduced over known devices for sharpening multi-blade cutters. This generally results in a much cleaner sharpening process so that, inter alia, the working conditions of an operator of said device are substantially enhanced.

[0018] It is to be understood that other sharpener tools than the preferred cup wheel could be disposed on the motor axis. It has been found through experience that this depends on the demands placed on the sharpening result to be achieved on the cutting edge of a multi-blade cutter.

[0019] In order to allow for particular easy feeding of the multi-blade cutter to the sharpener tool, it is advantageous if the holding table is movable relative to the cup wheel in such a manner that, when the motor stops, the cutter is no longer contacting the cup wheel. Together with the multi-blade cutter clamped thereon, the holding table may thereby be caused to move relative to the cup wheel either manually or automatically.

[0020] In order to speed up the overall processing of a multi-blade cutter, there is provided in another implementation variant that the device comprise an additional motor. This motor preferably serves to receive another sharpener tool. Just as with regard to the first motor, it is also advantageous to dispose a cup wheel onto the motor axis of the additional motor.

[0021] In order to optimally position the motors and their sharpener tools with regard to the multi-blade cutter, it is particularly advantageous if at least one motor is movable relative to the holding table. It is thereby advantageous if the motor is movable vertically with respect to the holding table. The vertical movability is thereby made use of for adjusting the sharpening depth for example. It is however particularly advantageous if the motor is additionally, or exclusively, movable horizontally with respect to the holding table. The horizontal movement of the motor permits for example to achieve an advancing or feeding movement which otherwise would be performed by the movable holding table.

[0022] Due to the movability of the motor, the work piece is not movable with respect to the tool only like usual, the tool is also movable with respect to the work piece. This more specifically applies to an advancing or feeding movement during the actual sharpening process.

[0023] The horizontal movability of at least one motor with respect to the holding table is also particularly advantageous if for example only one of the two motors is movable in the horizontal direction. For example, the multi-blade cutter is fed to a first cup wheel of a first motor by means of the holding table in a manner that is optimal for sharpening. Before however the sharpening process is initiated on the first blade of the multi-blade cutter, the second motor can be optimally positioned, together with its cup wheel, on the second blade of the multi-blade cutter in an advantageous manner. With the multi-blade cutter being thus positioned with respect to the two cup wheels of the two motors, the two blades of the multi-blade cutter may be sharpened in one process.

[0024] In order for example to simplify the entire processing of the multi-blade cutter, it is advantageous to have a holding element disposed on the holding table, said holding element being rotatable 180° in a plane of the holding table.

[0025] A holding element is advantageous in order for example to position the multi-blade cutter faster and more easily in the sharpening device. If for example a first blade of the multi-blade cutter was sharpened and if thereafter the second blade of the multi-blade cutter is to be positioned for sharpening with respect to the sharpener tool, this may be achieved more easily if the multi-blade cutter is disposed on a holding element. Accordingly, the holding element serves to receive the multi-blade cutter. The multi-blade cutter is preferably secured to the holding element before the holding element itself is disposed on the holding table. This makes it possible to prepare a plurality of multi-blade cutters to be sharpened, for example to speed up passage of the cutters through the sharpening device. One multi-blade cutter is for example disposed on a respective holding element, with the holding elements, which include the multi-blade cutters, being fed one after the other to the holding table.

[0026] With regard to an automation of the device of the invention, it is advantageous if the holding element is adapted to be supplied to the holding table.

[0027] This also applies to supplying the holding element to the motors.

[0028] It is thereby possible to feed or discharge multiple holding elements with multi-blade cutters disposed thereon by means of a conveyor system so that for example, after sharpening of the blades of one multi-blade cutter is completed, this cutter is moved, together with the holding element, either by hand or, preferably, automatically, away from the device and another holding element carrying the multi-blade cutter is fed to the device.

[0029] In accordance with the invention it is proposed that it is advantageous if the device comprises a control panel that is disposed in the side region of the sharpening device.

[0030] Preferably, the term “side region” is to be construed herein as the region that is located along the main shifting axis of the holding table.

[0031] The advantage of disposing the control panel in the side region is that the actual sharpening process can be much better surveyed by the operator. This enables for example much easier correction of the sharpening angle, the sharpening depth or of other process parameters.

[0032] The term “control panel” thereby preferably refers to all of the structural components of the device that are used for advantageous and easy operation of the device with regard to electrical and/or mechanical components of the device.

[0033] In order for example to insert a new multi-blade cutter into the sharpening device or to rotate 180° within the device a multi-blade cutter the first blade of which has already been sharpened, it is advantageous if the device comprises a protective cap the pivot axis of which is disposed in the direction of the main shifting axis of the holding table. If the pivot axis of the protective cap is disposed in the direction of the main shifting axis, the protective cap can be of a particular simple construction and will be easy to operate.

[0034] Another advantage is that insertion, repositioning and removing of the multi-blade cutter may be configured to be much easier than if the pivot axis were disposed transversely to the main shifting axis of the holding table.

[0035] In order for example to achieve for a blade of the multi-blade cutter a higher sharpening quality, it is advantageous if the device comprises a microspraying system for providing cooling during the sharpening process. The great advantage of a microspraying or microcooling system over conventional cooling systems utilized hereto before in devices for sharpening multi-blade cutters is that the region where the processing or rather sharpening takes place is not excessively contaminated by the coolant. Moreover, in the microspraying system, there is no recirculation of the excess coolant into a collecting tank. As a result, the cooling system may advantageously be of a particularly simple construction. Utilizing a microspraying system, the coolant supply and the sprayed particles are preferably selected so that all of the supplied coolant will evaporate. This permits to better protect the processing volume, and more specifically the work piece, from excess contamination by the spray fluid or the spray dust.

[0036] Utilization of a microspraying system is particularly advantageous when used in connection with a boron nitrite cup wheel since, as already described herein above, but very little dust susceptible to mixing with the coolant is produced during sharpening, when using a boron nitrite cup wheel.

[0037] Advantageously, the small amounts of dust produced during sharpening and the small quantities of coolant supplied by means of the microspraying system hardly soil the processing volume of the device so that this more specifically positively affects cleaning and maintenance of the device of the invention.

[0038] Another solution to the object of the invention is a method for sharpening multi-blade cutters by which two blades of the multi-blade cutter are sharpened simultaneously and symmetrically. It may be readily recognized that, inter alia, the processing time of a multi-blade cutter with for example two blades will be reduced by almost half as compared to a conventional device for sharpening multi-blade cutters.

[0039] Further advantages, objects and properties of the present invention will become apparent upon reading the description of the appended drawings illustrating by way of example devices for sharpening multi-blade cutters.

[0040] In the drawings:

[0041]FIG. 1 is a perspective top view of the processing region of a device for sharpening multi-blade cutters in accordance with the invention,

[0042]FIG. 2 is a perspective top view of the processing region of the device in accordance with the invention of FIG. 1, when viewed from the side,

[0043]FIG. 3 is a schematic view of the device of FIG. 1 and of FIG. 2,

[0044]FIG. 4 is another schematic view of the device of FIGS. 1 and 2,

[0045]FIG. 5 is a perspective top view of an alternative device for sharpening multi-blade cutters with two motors,

[0046]FIG. 6 is a schematic top view of the alternative device of FIG. 5,

[0047]FIG. 7 is another schematic view of a front side of the alternative device of FIG. 5,

[0048]FIG. 8 is a schematic view illustrating the functioning principle of a microspraying system for the device in accordance with the invention,

[0049]FIG. 9 is a schematic top view of a multi-blade cutter secured by means of a quick clamping device,

[0050]FIG. 10 is a perspective partial view of the fixed multi-blade cutter of FIG. 9,

[0051]FIG. 11 is a detail side view of one half of a quick clamping device with a threaded rod,

[0052]FIG. 12 is a perspective top view of the entire quick clamping device interacting with a threaded rod,

[0053]FIG. 13 is a schematic top view of a sharpening device for a brush cutter,

[0054]FIG. 14 is a top view of a brush cutter,

[0055]FIG. 15 is a schematic view of a sharpening device for chopper blades,

[0056]FIG. 16 is a schematic section through the device shown in FIG. 15 taken along the line XVI-XVI,

[0057]FIG. 17 shows multiple views of a flail cutter,

[0058]FIG. 18 is a schematic top view of a holding member for a flail cutter,

[0059]FIG. 19 is a schematic side view of a holding member for a flail cutter,

[0060]FIG. 20 shows two schematic views of a topper,

[0061]FIG. 21 is a schematic view illustrating a top view of a holding member with a topper clamped thereon and

[0062]FIG. 22 is a schematic view of a side view of the mounting shown in FIG. 21.

[0063] The device 1 shown in the FIGS. 1 and 2 comprises a holding table 2, two fixing devices 3 and 4, one motor 5 with a motor axis 6 on which there is disposed a sharpening disc 7 and a holding member 8. In the instant exemplary embodiment, the holding member 8 includes a slide rod clamp 9. A hollow pressure pot 11 is disposed on one shaft end 10 of the slide rod clamp 9. The holding member 8 is disposed on the fixing member 4 by means of the clamping means 12. The holding table 2 moreover comprises a plurality of additional clamping means 13, 14, 15, 16. The cavity in the pressure pot 11 thereby serves to receive a centering point of the fixing member.

[0064] A multi-blade cutter 17 is placed onto the holding table 2 in such a manner that it is fixedly secured at its symmetry point 18 on the holding table 2 by means of the holding member 8.

[0065] The multi-blade cutter 17 has two blades 19 and 20 that are sharpened one after the other by means of the cup wheel 7. The multi-blade cutter 17 is not only fixed at its symmetry point 18, it is additionally secured to two dogs 21 and 22 of the holding table. The two dogs 21 and 22 are adjusted relative to the holding table 2 by the clamping means 14 and 16 respectively so as to achieve an optimal position for sharpening the multi-blade cutter 17.

[0066] For sharpening, the holding table 2 is moved toward the cup wheel 7 of the motor 5 along the two double arrows 23 and 24. The multi-blade cutter 17 is moved toward, or rather supplied to, the sharpening disc 7 automatically. In this exemplary embodiment, the advancing movement of the holding table 2 in the left direction of the main shifting axis 24 is performed automatically during the actual sharpening process of the blades 19 and 20.

[0067] Once the sharpening process of blade 19 is completed, the holding table 2 is moved relative to the motor 5 into a position where it is ready for processing. In this position, in which the work piece is ready to be processed, the lock of the slide rod clamp 9 is released and the multi-blade cutter 17 is removed from its fixation and rotated 180° with respect to the plane of the holding table so that the blade 20 can be sharpened in the manner described herein above after having been fixed anew by the slide rod clamp 9 by means of the cup wheel 7.

[0068] Each of the fixing members 3 and 4 are bent to a 90 degree angle in their rear region 25 and 26. The bent ends 27 and 28 of the fixing members 3 and 4 are configured in such a manner that a holding member 8 can be fixed thereon by means of the clamping means 12 in a fast and simple manner. As a result thereof, the holding member 8 is fixable relative to the holding table 2.

[0069] The holding table 2 of device 1 is not only movable in the direction of the main shifting axis 24 and in the direction of the shifting axis 23, it is also movable along the shifting axis 29.

[0070] The shifting axis 29 is oriented such that it extends at right angles into the page. The holding table 2 can thus be shifted vertically relative to the motor 5.

[0071] The motor 5 can be moved along the shifting axis 29, in the directions 30 and 31 resp. In addition thereto, the motor 5 is carried to pivot about an axis 32. The pivot axis 32 of the motor 5 extends in the direction of the main shifting axis 24.

[0072] In order to further optimize the sharpening process, the multi-blade cutter 17 is rotatable 180° about its symmetry point 18 with respect to a plane of the holding table 2. If for instance the processing of blade 19 is completed, the multi-blade cutter 17 is rotated 180° in the direction indicated by the arrows 33 and 34 so that the blade 20 is moved into immediate proximity to the cup wheel 7.

[0073] The alternative device 35 of FIG. 5 includes, along the direction indicated by the arrow 36, a movable holding table 37, a first motor 38 and an additional motor 39. The holding table 37 is adapted to be displaced along an axis 40. The motor 38 is movable in a vertical direction 41 with respect to the holding table 37. The motor 38 includes a motor axis 42 at the end of which there is disposed a sharpening disc 43. The motor 39 of device 35 is movable in a vertical direction 44 with respect to the holding table 37 and is, in addition thereto, also movable in a horizontal direction 45 with respect to the holding table 37.

[0074] The horizontal direction 45 is substantially parallel to the main shifting axis 36 of the holding table 37. The motor 39 includes a motor axis 46 at the end of which there is disposed a cup wheel 47.

[0075] A multi-blade cutter secured to the holding table 37 is schematically denoted by its two blades 48 and 49 as well as by its symmetry point 50 only.

[0076] The holding table 37 with the multi-blade cutter disposed thereon is now supplied to the cup wheel 43 of the motor 38 in such a manner that the cup wheel 43 is optimally positioned with respect to the blade 48. Additionally, the cup wheel 47 can be moved toward the blade 49 along the axis 45. If the two motors 38 and 39 have their cup wheels 43 and 47 optimally positioned on a respective one of the blades 48 and 49, the holding table 37 is moved together with the multi-blade cutter in the direction of the main shifting axis 36, the blades 48 and 49 being sharpened thereby. The respective sharpening depth can be adjusted by shifting the motors 38 and 39 along the directions 41 and 44.

[0077] It is to be understood that, in this exemplary embodiment as well, the motors 38 and 39 can be pivoted about a pivot axis 51 and about a pivot axis 52 respectively in order to adjust the cutting angle.

[0078] In order for example to optimally position the motors 38 and 39 with respect to the holding table 37, said motors 38 and 39 can be moved in a direction 53 and in a direction 54 respectively so that the cup wheels 43 and 47 can be optimally positioned with respect to a multi-blade cutter for almost any application.

[0079] It is to be understood that, depending on the application, the holding table 37 may only be moved in the main shifting axis 36 so that the advancing movement only, more specifically the advancing movement during the sharpening process, is performed. Positioning of the respective motors 38 and 39 then occurs along the shifting axes 45, 53 and 54.

[0080] If a device for sharpening multi-blade cutters 1, 35 is equipped with a microspraying system 55, said microspraying system preferably consists, inter alia, of an outer tube 56 into which a second, smaller tube 57 is inserted. The region 58 of the microspraying system 55 hereby forms a nozzle. By inserting tube 57 into tube 56, the section is reduced in a region 59 so that the flow velocity of the compressed air 60 applied is increased in this region. This physical effect creates a negative pressure at the tube opening 61 of the inserted tube 57, said negative pressure being used to draw coolant 62 from a vessel 63. In this exemplary embodiment, the intake quantity can be adjusted by varying the air pressure 60 applied and by providing a throttle valve 64 that is mounted into the tube 57. The air-coolant mixture 65 is supplied to the proximity of the respective one of the blades 19, 20, 48, 49 to be sharpened via a tubing mounted downstream thereof.

[0081] The multi-blade cutter 66 shown in FIG. 9 is secured at its symmetry point 67 to a holding element 69 by means of a quick clamping device 68. In order to prevent the multi-blade cutter 66 from rotating during the sharpening process, the multi-blade cutter 66 is additionally fixed to the holding element 69 by means of a clamping means 70.

[0082] The quick clamping device 68 preferably includes two halves 71 and 72, the two halves 71 and 72, which are assembled to form the quick clamping device 68, comprising a bore 73 along their central axis.

[0083] The half 71 hereby comprises two lugs 74 and 75, which mate with corresponding grooves provided in the half 72, thus performing the function of an adjusting device of the quick clamping device 68. Both half 71 and half 72 have a thread 77 in the top region 76 of the bore 73, said thread mating with the thread of a threaded rod 78 of a central point of the holding table 2, 37.

[0084] Two thirds of the length of bore 73 have a larger diameter 79 than the threaded rod 78 so that a clearance is provided in this region 79 between the threaded rod 78 and half 71 and half 72. Both half 71 and half 72 have two circumferential grooves 80 and 81 in the respective one of which there may be disposed a rubber ring 82.

[0085] Above groove 80 there is disposed a conical region 83 by means of which the self-centering quick clamping device 68 can be drawn along the threaded rod 78 into the symmetry point 67 of the multi-blade cutter 66.

[0086] If for instance the quick clamping device 68 is not yet disposed in the region of the centering point 18 of the multi-blade cutter 66, the halves 71 and 72 of the quick clamping device 68 are held together by means of at least one rubber ring 82.

[0087] In this exemplary embodiment, the thread 77 is configured to be a “V” thread, which considerably facilitates handling during clamping and releasing of the quick clamping device. It has been found out that it is not necessary to use a trapezoidal thread, which has a greater carrying capacity.

[0088] In lieu of a rubber ring 82, or in addition thereto, the two halves 71 and 72 can also be fixed relative to each other by means of at least one hinge connection.

[0089] The sharpening device 90 shown in FIG. 13 substantially consists of the holding table 91. The function of the holding member is performed by the carrier plate 92 by means of the centering bolt 93 for disposing a brush cutter 94 onto the carrier plate 92. By means of the fixing devices 95 and 96, said carrier plate is disposed so as to be movable along the main shifting axis 97. Two blades 98 and 99 of the brush cutter 94 are respectively disposed parallel to the main shifting direction 97. This permits to sharpen at an accurate angle using the sharpening disc 101 disposed on the motor 100. The accurate orientation of the brush cutter, with the blades 98 and 99 being parallel to the main shifting axis 97, is adjusted and fixed by a stop plate 102, the brush cutter being prevented from moving in the axial direction of the centering bolt 93 by a holding-down clamp 103.

[0090] For using the sharpening device, the dog 102 is first removed by means of the clamping lever 104. Then, the carrier plate 92, with all of the component parts, is placed onto the holding table 91. The plain position between carrier plate 92 and holding table 91 is secured by the fixing or alignment pin 105 and 106. By means of said fixing pins 105 and 106, the carrier plate 92 is oriented normal to the direction of movement 97. The carrier plate 92 is next secured to the holding table 91 by tightening the screw 107. The replacement centering bolt 93 permits to hold brush cutters 94 having different receiving bores of for example 20 mm or 25.4 mm in diameter.

[0091] In order to receive the brush cutter 94 in the centering bolt 93, the stop plate 102 above the associated clamp 104 is released and displaced to the left in FIG. 13. Then, the cutting edges 98 and 99 of the brush cutter 94 can be oriented parallel to the outer edge of the carrier plate 92. Sharpening will first be performed on the cutting edge side showing the greatest wear.

[0092] Prior to sharpening, the stop plate 102 is pushed into the radius of the brush cutter's outer edges where it is secured by clamping. This clamping securement makes certain that the brush cutter 94 has its cutting faces oriented parallel to the direction of movement 97. This orientation and fixation applies to all sides of the cutter. Thanks to this method it is made certain that, after having sharpened the cutter allover, all of the cutter's sides are symmetrical, meaning that they have been sharpened so as to have the same length and the same alignment, so that the unbalancing effect of the blades is minimized as compared to manual sharpening, using for example a belt sharpener. As a result thereof, it is no longer necessary to control the sharpening result using a sharpening template. In order to prevent the sharpening forces from lifting the brush cutter 94 from the carrier plate 92 during processing, the brush cutter 94 is clamped to the carrier plate 92 using the holding-down clamp 103 prior to sharpening.

[0093] After processing all the three sides of the brush cutter 94 both on the front and on the rear side using this method, sharpening is then completed. Depending on the manufacturer's advice, another blade geometry may also be sharpened.

[0094] The feed depth is limited in the same manner as when sharpening lawn mower cutters, that is by a feed stop provided on the motor 100, said feed stop limiting manual or automatic supply and thus considerably contributing to achieving high balance quality.

[0095]FIG. 14 schematically illustrates a brush cutter the blades 108 of which are disposed at an angle of 120°.

[0096] The FIGS. 15 and 16 show how to sharpen a chopper in much the same way. The sharpening device 110 is provided with a holding table 111 onto which a chopper 113 is clamped by means of a holding member 112. The holding member 112 hereby pushes a holding strap or holding-down member against the chopper 113 by means of a screw 114. The holding-down member may also be configured to be a clamp or a clamping claw. For sharpening the chopper 113, the holding table 111 is moved together with the chopper 113 along the main shifting direction 15 with respect to the sharpening disc 116 in order to achieve a straight, accurately angled sharpening result. The FIGS. 18 and 19 show a device 120 for sharpening a flail cutter 121 shown in FIG. 17. For this purpose, there is again provided a holding table 133 to which the flail cutter is secured by means of a holding member 123. The flail cutter is firmly secured by clamping using on the one side a height-adjustable cone 124 and on the other side an adjustable clamping means 135 and a holding-down member 126. The holding-down clamp 126 is thereby fixable by means of a rocker lever 127. Again, the axis 128 of motor 129 is disposed normal to the main shifting direction 130 in order to achieve uniform sharpening of the flail cutter 121.

[0097] The FIGS. 21 and 22 show a sharpening device 140 for sharpening a topper for a sugar beet harvester as illustrated in the 2 views shown in FIG. 20. For sharpening these special cutters, there is again provided a holding table 141 that is movable parallel to the cup wheel 144 in a main shifting direction 143 by means of a fixing device 142 described herein above. On the fixing device there is disposed a carrier 145 that is easy to remove using the clamping means 146. The topper 148 is screwed onto the carrier by means of a screw 147. The topper is thereby additionally held by the stop plate 149 which is adjustable in its position by means of the clamping means 150 in such a manner that the blade 151 of the chopper 148 is disposed parallel to the main shifting direction 143.

[0098] All of the devices described permit, by replacing the carrier plate, the stop plate and the holding-down member, to clamp completely different cutters in such a manner that their blade is parallel to the main shifting direction and is guided normal to the motor axis. Quick clamping devices are additionally provided for quickly replacing the cutters to be processed while stop plates, which are properly adjusted once and for all, ensure proper orientation of the blades. 

1. A device (1; 35) for sharpening multi-blade cutters (17; 66) having at least one motor (5; 38, 39) and a holding table (2; 37) that is mobile relative thereto, said holding table (2; 37) comprising a holding member (8) for clamping (18; 50; 67) the cutter (17; 66), wherein a motor axis (6; 42, 46) of the motor (5; 38, 39) is disposed crosswise to the main shifting axis (24; 36) of the holding table (2; 37).
 2. The sharpening device (1; 35) according to claim 1, wherein the holding member (8) is disposed on the holding table by means of a fixing member (3, 4).
 3. The sharpening device (1; 35) according to claim 1, wherein the device (1; 35) comprises at least one more fixing member (3, 4) for a holding member (8).
 4. The sharpening device (1; 35) according to claim 1, wherein the holding member (8) is disposed so as to be detachable.
 5. The sharpening device (1; 35) according to claim 1, wherein the holding member (8) includes a holding-down clamp.
 6. The sharpening device (1; 35) according to claim 1 wherein the holding member (8) includes a slide rod clamp (9).
 7. The sharpening device (1; 35) according to claim 1, wherein the holding member (8) is fixable relative to the holding table (2; 37).
 8. The sharpening device (1; 35) according to claim 7, wherein a cup wheel (7; 43, 47) is disposed on the motor axis (6; 42, 46).
 9. The sharpening device (1; 35) according to claim 1, wherein the holding table (2; 37) is movable relative to at least one cup wheel (7; 43, 47).
 10. The sharpening device (1; 35) according to claim 1, wherein the device (1; 35) includes at least one more motor (5; 38, 39).
 11. The sharpening device (1; 35) according to claim 1, wherein at least one motor (5; 38, 39) is movable relative to the holding table (2; 37).
 12. The sharpening device (1; 35) according to claim 1, wherein a holding element (69) which is preferably rotatable 180° in a plane of the holding table is disposed on said holding table (2; 37).
 13. The sharpening device (1; 35) according to claim 12, wherein the holding element (69) is adapted to be supplied to the holding table (2; 37).
 14. The sharpening device (1; 35) according to claim 12, wherein the holding element (69) is adapted to be supplied to the motors (5; 38, 39).
 15. The sharpening device (1; 35) according to claim 1, wherein a control panel which is disposed in the side region of the sharpening device.
 16. The sharpening device (1; 35) according to claim 1, wherein a protective cap the pivot axis of which is disposed in the direction of the main shifting axis (24; 36) of the holding table (2; 37).
 17. The sharpening device (1; 35) according to claim 1, wherein a microspraying system (55) for providing cooling during the sharpening process.
 18. (canceled) 